The invention relates to a junction structure for connecting two profiles, in particular in a vehicle support frame, the first profile of which has at least two planar, parallel sides and the second profile consists of two parallel, opposite girders and at least one strip, connecting the girders, whereby the girders with their lateral ends project relative to the strip, these projections forming paired parallel flanges, and whereby the first profile at the location of connection has a recess, into which the second profile is inserted on the front side in such a manner that the parallel sides of the opposite ends of the first profile limiting the recess, rest in a form fit against the insides of the opposite flanges of the second profile and are connected thereto.
For some years particularly in the construction of vehicles before the background of new lightweight construction concepts, hollow profiles, that is to say profiles with a closed cross section, are again increasingly being used. In particular such hollow profiles, which are produced from high and maximum strength steel materials, offer a high weight reduction potential. A central problem area in the use of hollow profiles concerns their joining together by means of connecting junctions.
Junction structures for connecting profiles, in particular hollow profiles, have been known for a long time. Thus European Patent EP 0 568 251 B1 describes a T-shaped junction structure for joining a cross member configured as a hollow profile with a rectangular cross section to the side rocker rail. In accordance with one embodiment of such a T-junction the cross member at its one end is split lengthwise and bent up so as to form two profiles with C-shaped cross section, arranged flush with one another, bent about 90° in each case, against which the side rocker rail is placed and welded thereto. As a result a junction structure with a large contact zone and high strength associated therewith can be realized, which in addition provides tolerance compensation in the vehicle longitudinal direction, however linked with this is the comparatively high production cost due to the respective need for individual working of the cross member end. Also, in the event of a front or rear collision, that is to say if force is applied to the vehicle frame in the longitudinal direction, the weld seam can tear, whereby the connection between cross member and side rocker rail is completely broken and the vehicle support frame to a large extent loses strength.